JPH11227631A - Cab suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the difference in the comformableness between the trailer coupled condition and non-coupled condition. SOLUTION: A cab suspension control device is applied to a vehicle of such a structure that a cab is supported on a chassis for towing a trailer and is composed of a shock absorber (a) interposed between the can and chassis and capable of changing the damping force characteristic, a cab behavior detecting means (b) to detect the behavior of the cab, and a damping force characteristic control means (c) which controls the damping force characteristic of each shock absorber (a) on the basis of the cab behavior signal given by the detecting means (b). The arrangement further includes a trailer coupling detecting means (d) to detect whether vehicle and trailer are in coupling and a control characteristic changeover means (e) which changes over the operating characteristics in controlling the damping fore characteristic of the shock absorber (a) made by the control means (c) depending upon coupling or not decided by the detecting means (d).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cab-over
TECHNICAL FIELD The present invention relates to a cab suspension control device that optimally controls a damping force characteristic of a shock absorber interposed between a cab side and a chassis side in a vehicle of a type.

[0002]

2. Description of the Related Art Conventionally, as a cab suspension device for controlling damping force characteristics of a shock absorber, for example, a "cab suspension device" described in Japanese Utility Model Laid-Open No. 4-115906 is known. This conventional example has a shock absorber with a variable damping force characteristic between a cab and a tractor body, and a trailer truck in which a trailer is connected to a rear part of the body via a coupler. Load detecting means for detecting a load inserted in the tractor and acting in the longitudinal direction of the tractor; extracting means for extracting only low-frequency components from the detection output of the load detecting means; It is provided with a calculating means for calculating a force, and a shock absorber driving means for switching a damping force of the variable damping force characteristic type shock absorber based on a calculation output of the calculating means. This conventional device calculates the reaction force in the tractor front-rear direction based on the load acting on the tractor from the trailer in the front-rear direction, and switches the damping force of the damping force characteristic variable type shock absorber from this calculation output.
The purpose is to suppress cab pitching and to ensure riding comfort.

[0003]

However, in the above-described conventional apparatus, the behavior of the cab can be accurately controlled in a state where the trailer is connected to the tractor, but in a state where the trailer is not connected. Therefore, when the trailer is not connected, the control cannot be executed because the load detecting means does not detect the load. Therefore, there is a problem that a great difference occurs in ride comfort between the trailer connection state and the non-connection state. The present invention has been made in view of the above-mentioned problems of the conventional device, and detects whether the tractor is in a connected state or in a non-connected state, switches the control characteristics in the damping force characteristic control, and performs a shock absorber in each state. It is an object of the present invention to provide a cab suspension control device capable of optimally controlling a damping force characteristic of a cab.

[0004]

According to a first aspect of the present invention, there is provided a cab suspension control device according to the first aspect of the present invention, wherein a cab is supported on a chassis and a trailer is mounted on the chassis, as shown in FIG. A shock absorber a that is interposed between the cab side and the chassis side and configured to be capable of changing a damping force characteristic, of a vehicle configured to be towable,
Cab behavior detecting means b for detecting the behavior of the cab;
A cab suspension control device comprising: a damping force characteristic control unit c for controlling a damping force characteristic of the shock absorber a based on the cab behavior signal detected by the cab behavior detection unit b. A control characteristic of the trailer connection detecting means d for detecting whether or not the vehicle is connected, and the control characteristic of the damping force characteristic control of the shock absorber a by the damping force characteristic control means c according to the presence or absence of the connection detected by the trailer connection detecting means d. And control characteristic switching means e for switching between the two. According to a second aspect of the present invention, in the cab suspension control device according to the first aspect, the control characteristic switching means e is configured to switch a control characteristic by switching a control constant according to the presence or absence of the connection. And
According to a third aspect of the present invention, in the cab suspension control device according to the first or second aspect, the cab behavior detecting means b detects a vertical speed of the cab, and based on the detected value, a bounce speed, a pitch speed, and a roll speed. Is obtained.

(Operation) In the cab suspension control device of the present invention, when the trailer connection is detected by the trailer connection detecting means d, the damping force characteristic control means c causes the damping force characteristic control means c to attenuate the shock absorber a in the control characteristic switching means e. The control characteristics in the force characteristic control are switched to those suitable for the cab behavior in the trailer connection state. This makes it possible to optimally control the behavior of the cab when the trailer is connected, thereby ensuring the stability and riding comfort of the cab. When the trailer connection is not detected by the trailer connection detecting means d, the control characteristics in the control of the cab behavior in the non-trailer connected state are controlled by the control characteristics switching means e in the control of the damping force characteristics of the shock absorber a by the damping force characteristic control means c. Switch to the one that matches. This makes it possible to optimally control the behavior of the cab when the trailer is not connected, thereby ensuring the stability and riding comfort of the cab. Therefore, by performing optimal control according to the respective states of the trailer connection state and the non-connection state, it is possible to reduce the difference in riding comfort between the trailer connection state and the non-connection state. Claim 2
In the described invention, different control constants are set in the trailer connection state and the non-connection state, and the control characteristics are switched by switching the control constants. Therefore, the control characteristics can be easily switched. it can. According to a third aspect of the present invention, the cab behavior detecting means b detects the vertical speed of the cab, and the bounce pitch
Since the damping force characteristic control of the shock absorber a is performed after the roll speed is obtained, the behavior of the cab can be more precisely controlled.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a configuration explanatory view showing a cab suspension control device according to an embodiment of the present invention. The present embodiment is applied to a vehicle for towing a trailer (not shown). And between chassis 6
Four shock absorbers SA _FL , SA _FR , SA _RL , S
A _RR (The sign after the shock absorber SA indicates the position where the shock absorber is provided. _FL is the front left, _FR is the front right,
_RL indicates the rear left, and _RR indicates the rear right. In the description of these shock absorbers, when a specific one is not indicated, it is simply displayed as SA. (Note that FIG. 2 shows only the components provided on the left side of the chassis.) The cab 5 and the chassis 6
An air spring 36 is interposed between each of the shock absorbers SA at a position near each shock absorber SA.

[0007] The cab 5 is arranged at two locations on the left and right sides on the front side and one location on the center on the left and right sides so as to form a triangular shape. , Downwardly negative values) are provided with sprung vertical acceleration sensors (hereinafter, referred to as vertical G sensors) 1 _FL , 1 _FR , and 1 _RC (the code _FL attached to “1” of these G sensors). , _FR , and _RC also indicate the positions where they are provided, and unless otherwise indicated, simply indicate "1"). A trailer connection sensor 2 is provided behind the cab 5 to detect whether or not the trailer is connected based on whether or not the tractor-side wiring connector 8 and the trailer-side wiring connector 9 are connected.

The sensors 1 and 2 are connected to a control unit 4. This control unit 4
As shown in FIG. 3, a vehicle speed sensor 10 for detecting a vehicle speed of a vehicle, a steering sensor 11 for detecting a steering angle of a steering wheel, and whether or not a brake pedal is depressed, as shown in FIG. Is provided with a brake sensor 15 for detecting the above.

The control unit 4 sends a drive control signal to the pulse motor 3 of each shock absorber SA based on signals from the G sensor 1, the trailer connection sensor 2, the vehicle speed sensor 10, the steering sensor 11, and the brake sensor 15. The control unit 4 includes an interface circuit 4a, a CPU 4b, and a drive circuit 4c.
_Sprung vertical acceleration signal G from sensors 1 _FL , 1 _FR , 1 _RC
FL , G _FR , G _RC , ON, O from trailer connection sensor 2
A trailer connection signal of the FF, a vehicle speed signal VB from the vehicle speed sensor 10, a steering angle signal H from the steering sensor 11, and an ON / OFF brake signal from the brake sensor 15 are input.

FIG. 4 is a sectional view showing the structure of the shock absorber SA.
A is a cylinder 30, a piston 31 that defines the cylinder 30 in an upper chamber A and a lower chamber B, an outer cylinder 33 in which a reservoir chamber 32 is formed on the outer periphery of the cylinder 30, a lower chamber B and a reservoir chamber 32. Base 34 and piston 31
A guide member 35 for guiding the sliding of the piston rod 7 connected to the outer cylinder 33, a suspension spring 36 interposed between the outer cylinder 33 and the vehicle body, and a bump rubber 37.

FIG. 5 is an enlarged sectional view showing a portion of the piston 31. As shown in FIG. 5, the piston 31 has through holes 31a and 31b formed therein, and A compression-side damping valve 20 and an extension-side damping valve 12 for opening and closing 31a and 31b, respectively, are provided. A stud 38 that penetrates the piston 31 is screwed and fixed to a bound stopper 41 screwed to the tip of the piston rod 7, and the stud 38 bypasses the through holes 31a and 31b. Communication for forming flow paths (extension-side second flow paths E, expansion-side third flow paths F, bypass flow paths G, and compression-side second flow paths J to be described later) that communicate the upper chamber A and the lower chamber B. A hole 39 is formed.
An adjuster 40 for changing the flow path cross-sectional area of the flow path is rotatably provided in 9. Also, stud 38
The communication hole 3 is formed on the outer periphery of the communication hole 3 in accordance with the direction of fluid flow.
An expansion-side check valve 17 and a compression-side check valve 22 that allow and shut off the flow on the flow path side formed by 9 are provided. Note that the adjuster 40 is provided with the pulse motor 3.
Is rotated through the control rod 70 (see FIG. 4). Also, studs 38
A first port 21, a second port 13, a third port 18, a fourth port 14, and a fifth port 16 are formed in this order from the top.

On the other hand, the adjuster 40 has a hollow portion 19, a first horizontal hole 24 and a second horizontal hole 25 communicating between the inside and the outside, and a vertical groove 23 formed in the outer peripheral portion. I have. Therefore, between the upper chamber A and the lower chamber B, as a flow path through which fluid can flow in the extension stroke, the through hole 3 is provided.
1b, a first flow path D extending to the lower chamber B by opening the inside of the expansion damping valve 12, a second port 13, a longitudinal groove 2
(3) a second expansion passage (E) that opens the outer peripheral side of the expansion damping valve (12) through the fourth port (14) to reach the lower chamber (B);
The extension side check valve 17 is opened via the port 13, the vertical groove 23, and the fifth port 16, and the extension side third valve reaching the lower chamber B is opened.
The flow path F, the third port 18, the second lateral hole 25, and the hollow portion 19
There are four flow paths of a bypass flow path G which leads to the lower chamber B via. Also, as a flow path through which fluid can flow in the pressure stroke,
The upper chamber A is opened by opening the first pressure passage H through the through hole 31a and opening the first check passage 22 through the hollow portion 19, the first lateral hole 24, and the first port 21 to open the compression side damping valve 20. Pressure side second flow path J leading to the hollow portion 19, the second lateral hole 2
5, there are three flow paths: a bypass flow path G which reaches the upper chamber A via the third port 18.

That is, the shock absorber SA is configured so that the damping force characteristic can be changed in multiple steps by rotating the adjuster 40 with the characteristics shown in FIG. 6 on both the extension side and the compression side. That is, as shown in FIG. 7, when the adjuster 40 is rotated counterclockwise from a state where both the extension side and the compression side are soft (hereinafter, referred to as a soft region SS), the damping force characteristic of the extension side only is multi-stepped. And the compression side becomes a region where the compression side is fixed to the low damping force characteristic (hereinafter referred to as the extension side hard region HS). Conversely, when the adjuster 40 is rotated clockwise, the compression side only has a multi-stage damping force characteristic. An area in which the extension side can be changed and the extension side is fixed to the low damping force characteristic (hereinafter, the compression side hard area SH
).

By the way, in FIG. 7, when the adjuster 40 is arranged at the position of, K in FIG.
-K section (a), LL section and MM section (b),
FIGS. 8, 9 and 10 show NN cross sections (C), respectively, and FIGS. 11 and 1 show the damping force characteristics at each position.
2 and 13.

Next, the content of the damping force characteristic control operation in the control unit 4 will be described with reference to the block diagram of FIG. First, in the circuit B1, the sprung vertical accelerations G _FL , G _FR on the front left and right sides detected by the front left and right G sensors 1 _FL , 1 _FR of the cab 5 are used to calculate the front center position based on the following equation (1). The bounce component G _BF is obtained. G _BF = (G _FL + G _FR ) / 2 (1)

[0016] In the circuit B2, the spring at the side central positions after being detected by the rear center of the G sensor 1 _RC vertical acceleration G _RC
Then, the bounce component G _BR at the rear center position is obtained based on the following equation (2). G _BR = G _RC (2)

The circuit B3 calculates the vehicle pitch component _GP from the sprung vertical accelerations G _FL and G _FR at the front left and right positions and the sprung vertical acceleration G _{RC at the} rear center position based on the following equation (3). Ask. _{G P = ((G FL +} G FR) -2G RC) / 4 ... (3)

[0018] In circuit B4, front right and rear sprung side position vertical acceleration G _FR + G _RC, and, from the front left and rear on the side center of the spring vertical acceleration G _FL + G _RC, based on the following equation (4) , determine the roll component G _R of the vehicle. _{G R = (G FR -G FL} ) / 2 ... (4)

In a circuit B5 (speed converter) on the rear side of the circuits B1 to B4, a bounce component G at a front center position is provided.
_BF , the bounce component G _BR , the pitch component G _P , and the roll component G _R at the rear center position are respectively converted into the bounce component V _{BF at the} front center position by the sprung vertical speed, the bounce component V _{BR at} the rear center position, and the pitch component. V
_P, and converted into a roll component V _R. Note that this conversion includes
The phase lag compensation equation is used, and the general equation of the phase lag compensation can be expressed by the following transfer function equation (5). G _(S) = (AS + 1) / (BS + 1) (5) where A <B.

In addition, it has the same phase and gain characteristics as in the case where integration (1 / S) is performed in a frequency band (0.5 Hz to 3 Hz) required for damping force characteristic control, and has a low frequency (up to 0.05 Hz). The following transfer function equation (6) is used as a phase delay compensation equation for lowering the gain on the side of ()). G _(S) = {(0.001S + 1) / (10S + 1)} × γ (6) where γ is a gain for matching a gain characteristic with a signal when speed conversion is performed by integration (1 / S). In the embodiment of the present invention, γ is set to 10. As a result, as shown in the gain characteristic of the solid line in FIG. 15A and the phase characteristic of the solid line in FIG.
At 4 Hz, only the gain on the low frequency side is reduced without deteriorating the phase characteristics. Note that FIG.
The dotted lines (a) and (b) indicate the gain characteristic and the phase characteristic of the sprung vertical velocity signal whose speed has been converted by integration (1 / S), respectively.

In the subsequent circuit B6 (unnecessary frequency component removing section), a band-pass filter BPF process for improving the insulation of signals other than the target frequency band to be controlled is performed. That is, for both bounce components V _BF and V _BR , 2
The bounce component V _{bf at the} center position on the front wheel side and the bounce component V _{br at the} center position on the rear wheel side processed by using the next high-pass filter HPF (0.7 Hz) and the second-order low-pass filter LPF (0.8 Hz). Are obtained, and the pitch component V _P and the roll component V _R
About the second-order high-pass filter HPF (0.5H
By using z) and the second-order low-pass filter LPF (0.5 Hz), the processed pitch component _Vp and roll component _Vr are obtained. Each of the component signals is given a positive value in the upward direction and a negative value in the downward direction.

In the circuit B7 (control signal calculating section), independent bounce gains α _f and α _r are provided for the front side and the rear side, respectively.
And the pitch gain β and the roll gain r, and based on the following equations (7) to (10), each control signal V
Calculation processing for _obtaining (V _FR , V _FL , V _R ) is performed. Front right _{V FR = α f · V bf} + β · V P + r · V R ... (7) before the left _{V FR = α f · V bf} + β · V P -r · V R ... (8) after V _R = α in _{r · V br -β · V P} ... (9) circuit B8 (target damping force characteristic position calculating unit), the control signal _{V (V FR, V FL,} V R) from, on the basis of the flowchart shown in FIG. 16 The target damping force characteristic position P (P _T , P _C ) of each shock absorber SA is calculated. In the circuit B9 (pulse motor drive circuit), a drive signal is output to the pulse motor 3 toward the target damping force characteristic P calculated in the circuit B8.

Step 101 in the flowchart of FIG.
Then, it is determined whether or not the control signal V is a positive value.
If S, the process proceeds to step 102 to control each shock absorber SA to the extension-side hard area HS. If NO, the process proceeds to step 103. In step 103, the control signal V
Is determined to be a negative value. If YES, the routine proceeds to step 104, where each shock absorber SA is controlled to the pressure-side hard area SH, and if NO, the routine proceeds to step 105. Step 105 is a processing step performed when NO is determined in steps 101 and 103, that is, when the value of the control signal V is 0. In this case, each shock absorber SA is controlled to the soft area SS. I do.

When control is performed in the extension side hard region HS in step 102, the compression side damping force characteristic is fixed to the soft characteristic, but the extension side damping force characteristic (target damping force characteristic position P _T ) is expressed by the following equation. Based on (10), the control signal V
Change in proportion to. P _T = δ _T · V (10) where δ _T is a control constant on the extension side.

When the compression-side hard region SH is controlled in step 104, the extension-side damping force characteristic is fixed to the soft characteristic, but the compression-side damping force characteristic (the target damping force characteristic position P _C ) is expressed by the following equation (11). ) Is changed in proportion to the control signal V. P _C = δ _C · V (11) where δ _C is a pressure-side control constant.

The time chart of FIG. 17 is an example of the above-described damping force characteristic control.
Is a state in which the control signal V based on the sprung vertical speed is reversed from a negative value (downward) to a positive value (upward). At this time, the relative speed between the sprung and unsprung is still a negative value (shock). Since the stroke of the absorber SA is a pressure stroke side), at this time, the shock absorber SA is controlled to the extension side hard region HS based on the direction of the control signal V. Therefore, in this region, The pressure stroke side, which is the stroke of the shock absorber SA at that time, has soft characteristics.

In the region b, the control signal V remains positive (upward) and the relative speed between sprung and unsprung is changed from a negative value to a positive value (the stroke of the shock absorber SA is on the extension stroke side).
In this case, the shock absorber SA is controlled based on the direction of the control signal V at this time.
, And the stroke of the shock absorber is also an extension stroke. Therefore, in this region, the extension stroke side, which is the stroke of the shock absorber SA at that time, has a hard characteristic proportional to the value of the control signal V.

Area c is a state where the control signal V is reversed from a positive value (upward) to a negative value (downward).
At this time, the relative speed between the sprung and unsprung portions is still a positive value (the stroke of the shock absorber SA is on the extension stroke side). At this time, the shock absorber is determined based on the direction of the control signal V. SA is controlled to the compression side hard region SH, and therefore, in this region, the extension stroke side, which is the stroke of the shock absorber SA at that time, has soft characteristics.

In the region d, the relative speed between the sprung and unsprung is changed from a positive value to a negative value (the stroke of the shock absorber SA is on the extension stroke side) while the control signal V remains at a negative value (downward).
At this time, the shock absorber SA is controlled based on the direction of the control signal V at this time.
, And the stroke of the shock absorber is also a pressure stroke. Therefore, in this region, the pressure stroke side, which is the stroke of the shock absorber SA at that time, has a hard characteristic proportional to the value of the control signal V.

As described above, in this embodiment, when the control signal V and the sprung-unsprung relative speed have the same sign (regions b and d), the stroke side of the shock absorber SA at that time is set to the stroke side. The same control as the damping force characteristic control based on the skyhook control theory, in which the hardware characteristic is controlled, and when the sign is different (region a, region c), the stroke side of the shock absorber SA at that time is controlled to the soft characteristic. Is performed based only on the control signal V signal. Further, in this embodiment, the switching is performed when the stroke of the shock absorber SA switches, that is, when shifting from the area a to the area b and from the area c to the area d (from the soft characteristic to the hard characteristic). Since the position of the damping force characteristic on the stroke side has already been switched to the hardware characteristic side in the previous areas a and c, the switching from the soft characteristic to the hardware characteristic is performed without time delay, and as a result, the position is high. Control responsiveness is obtained, and switching from hardware characteristics to software characteristics is performed without driving the pulse motor 3, thereby improving the durability of the pulse motor 3 and saving power consumption. Will be done.

Next, FIG contents switching control of the which is a feature of the embodiment, the target damping force characteristic position P in the trailer coupling state and the non-connected state (P _T, P _C) 18
A description will be given based on the flowchart of FIG. Step 201
Then, the vehicle speed signal V is read from the vehicle speed sensor 10, and in the following step 202, it is determined whether or not the vehicle speed is 0, that is, whether or not the vehicle is stopped. If not 0, step 20
Go to 7. In step 203, the trailer connection sensor 2
At step 204, whether or not the trailer connection signal is ON, that is, whether or not the tractor-side wiring connector 8 and the trailer-side wiring connector 9 are connected and the trailer is connected. When it is determined that the trailer connection signal is ON and the trailer is connected, the process proceeds to step 205. When it is determined that the trailer connection signal is not ON and the trailer is not connected, the process proceeds to step 206. Proceed to.

[0032] At step 205 proceeds when the trailer coupling, the target damping force characteristic position P _T described above, equation for P _C (10), the control constant of the extension side of the equation (11) [delta] _T
And the pressure-side control constant δ _C are set based on the control map corresponding to the trailer connection state. On the other hand, in step 206 the process proceeds when the trailer uncoupled, equation (10), is set based on a control constant [delta] _C of the control constant [delta] _T and the compression side of the extension side of the equation (11) to the control map corresponding to the trailer uncoupled state .

In steps 207 and 208, FIG.
The sprung vertical acceleration is measured by the circuits B1 to B9 shown in FIG. 4 and a control signal corresponding to this is created. At this time,
By substituting the extension-side and compression-side control constants δ _T , δ _C set in step 205 or step 206 into equations (10) and (11), the extension-side and compression-side damping force characteristic positions P _T , P _C Set.

As described above, in the cab suspension control device according to the embodiment, the control constant δ _T on the extension side and the control constant δ _C on the compression side are switched between the connected state and the disconnected state of the trailer. By performing the optimal control of each shock absorber SA, the difference in ride comfort between the trailer connected state and the non-connected state can be reduced, and a good ride comfort can be obtained even in the trailer non-connected state. In order to prevent a difference in ride comfort between the trailer-connected state and the non-connected state in this way, the connection between the tractor-side wiring connector 8 and the trailer-side wiring connector 9 changes the trailer-connected state and the non-connected state. This can be achieved by adding a simple detection means to detect and when the trailer is not connected, by switching the control simply by switching the control constant, so that the existing device can be changed only slightly. There is an effect that the cost is excellent.

Further, in the present embodiment, in the damping force characteristic control based on the skyhook theory, the switching from the soft characteristic to the hard characteristic is performed without time delay, so that a high control response can be obtained and the hardware response can be improved. Switching from the characteristic to the soft characteristic is performed without driving the actuator, so that the pulse motor 3
, And power consumption can be saved.

Although the embodiments of the present invention have been described above, the specific configuration is not limited to the embodiments of the present invention, and even if there is a design change or the like within a range not departing from the gist of the present invention, the present invention is not limited thereto. Included in the invention. For example, in the present embodiment, the control is performed in the soft area SS only when the control signal is 0. However, a predetermined dead zone centered on 0 is provided and the control signal is shifted within the range of the dead zone. By maintaining damping force characteristics in the soft region SS, control hunting can be prevented. Further, in the embodiment of the invention, when the damping force characteristic of one of the extension stroke and the pressure stroke is variably controlled on the hardware side, the damping force characteristic on the reverse process side is softly fixed. Although the case where the shock absorber is used has been described, the present invention can of course be applied to a system using a shock absorber having a structure in which the damping force characteristics of the extension stroke and the compression stroke change simultaneously. Also, an example has been shown in which the trailer connection sensor 2 interlocked with the connection between the tractor-side wiring connector 8 and the trailer-side wiring connector 9 is used as the trailer connection detecting means. However, the present invention is not limited to this. A switch that is turned on when the vehicle is connected or disconnected, a dedicated switch that is connected when the trailer is connected, or a means for determining whether the trailer is connected or disconnected based on the load on the driving force or the movement of the cab May be used.

[0037]

As described above, in the cab suspension control device of the present invention, whether the trailer is connected or not is detected by the trailer connection detecting means, and the control characteristic switching means is provided based on the detected value. Is designed to switch the control characteristic in the damping force characteristic control of the damping force characteristic control means, so that it is possible to set the control characteristic in consideration of the difference in the behavior of the cab between the trailer connected state and the non-connected state, The effect is obtained that the difference in ride quality can be reduced so that a good ride quality can be obtained even when the trailer is not connected. According to the second aspect of the present invention, in the cab suspension control device according to the first aspect, the control characteristic switching means is configured to switch the control characteristic by switching a control constant depending on whether or not the trailer is connected. The switching can be easily performed, and the effect that the present invention device can be provided at a low cost with little change to the existing device can be obtained. According to a third aspect of the present invention, in the cab suspension control device according to the first or second aspect, the cab behavior detecting means detects the vertical speed of the cab, and based on the detected value, the bounce speed, the pitch speed, Because it is configured to calculate the roll speed, the behavior of the cab can be more precisely controlled to improve the balance between steering stability and ride comfort, and the control quality can be improved. Can be

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to a claim showing a cab suspension control device of the present invention.

FIG. 2 is a configuration explanatory view showing a cab suspension control device according to the embodiment.

FIG. 3 is a system block diagram of the embodiment.

FIG. 4 is a sectional view showing a shock absorber applied to the embodiment.

FIG. 5 is an enlarged sectional view showing a main part of the shock absorber.

FIG. 6 is a damping force characteristic diagram corresponding to a piston speed of the shock absorber.

FIG. 7 is a damping force characteristic diagram corresponding to a step position of a pulse motor of the shock absorber.

FIG. 8 is a sectional view showing the operation of the shock absorber.

FIG. 9 is a sectional view showing the operation of the shock absorber.

FIG. 10 is a sectional view showing the operation of the shock absorber.

FIG. 11 is a damping force characteristic diagram when the shock absorber is on the extension side hard.

FIG. 12 is a damping force characteristic diagram of the shock absorber in a soft state on an extension side and a compression side.

FIG. 13 is a damping force characteristic diagram of the shock absorber in a pressure-side hard state.

FIG. 14 is a block diagram of an embodiment.

FIG. 15 is a diagram showing a gain characteristic (a) and a phase characteristic (b) of a sprung vertical velocity signal converted using the phase delay compensation formula in the embodiment.

FIG. 16 is a flowchart showing a damping force characteristic control operation of the embodiment.

FIG. 17 is a time chart illustrating a damping force characteristic control operation of the embodiment.

FIG. 18 is a flowchart showing switching of control characteristics of damping force characteristic control according to the embodiment.

[Explanation of symbols]

a Shock absorber b Cab behavior detecting means c Damping force characteristic controlling means d Trailer connection detecting means e Control characteristic switching means SA _FL , SA _FR , SA _RL , SA _RR Shock absorber 1 _FL , 1 _FR , 1 _RC Vertical spring acceleration sensor 2 Trailer connection sensor 3 Pulse motor 4 Control unit 4a Interface circuit 4b CPU 4c Drive circuit 5 Cab 6 Chassis 8 Tractor side wiring connector 9 Trailer side wiring connector 10 Vehicle speed sensor 11 Steering sensor 15 Brake sensor _GFL , _GFR , _GRC up and down Acceleration signal VB Vehicle speed signal H Steering angle signal

Claims (3)

[Claims] 1. A vehicle having a cab supported on a chassis and capable of towing a trailer, wherein a shock absorber interposed between the cab side and the chassis side and configured to be capable of changing damping force characteristics is provided. A cab behavior detecting means for detecting the behavior of the cab; and a damping force characteristic control means for controlling a damping force characteristic of the shock absorber based on a cab behavior signal detected by the cab behavior detecting means. In the suspension control device, a trailer connection detecting means for detecting whether or not the vehicle and the trailer are connected, and a shock absorber by the damping force characteristic control means based on presence or absence of connection detected by the trailer connection detecting means. A control characteristic switching means for switching a control characteristic of the damping force characteristic control. Deployment control device. 2. The cab suspension control device according to claim 1, wherein said control characteristic switching means is configured to switch a control characteristic by switching a control constant according to the presence or absence of the connection. 3. The cab behavior detecting means is configured to detect a vertical speed of the cab and obtain a bounce speed, a pitch speed, and a roll speed based on the detected value. 3. The cab suspension control device according to claim 1.